Epidemiology and management of white rust and alternaria blight of Indian mustard

Studies were conducted to determine the role of weather conditions on the development of white rust and Alternaria blight in Indian mustard and to work out their control measures during 2011–12 and 2012–13 crop seasons. The development of white rust and Alternaria blight was favoured by a mean temperature ranging between 12.2–14.8°C and 12.2–20.1°C, respectively, along with an average relative humidity of more than 80 per cent. Highly significant positive correlation of the disease severity was observed between with temperature (maximum and minimum). Among seven fungicides tested, Ridomil Gold Mz @ 0.25% was found to be most effective against white rust while, Score 25EC @ 0.1% was the most effective treatment against Alternaria blight. Maximum increase in grain yield (31.6 per cent) was obtained with Ridomil Gold Mz @ 0.25%.